The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 31, 2001
Filed:
Feb. 17, 1999
Thaddeus Schroeder, Rochester Hills, MI (US);
Raymond O. Butler, Jr., Anderson, IN (US);
Bruno Patrice Bernard Lequesne, Troy, MI (US);
Delphi Technologies, Inc., Troy, MI (US);
Abstract
A detector of position of rotation of a target wheel via the outputs of a differential sensor employing two matched MRs to extract position of rotation information from the target wheel. The target wheel is provided with wide and narrow slots or teeth circumferentially arranged such that, for example, 24 zones are created wherein each zone ranges from the center of a wide slot to the center of a narrow slot, and wherein each zone occupies 15 degrees circumferentially. The two matched MRs of the sensor are powered by matched current sources and matched magnetic biasing and are aligned in the circumferential direction of the target wheel. The MRs generate two angularly offset signals from the passage of a single slot (or tooth) of the target wheel which are input to a signal conditioning circuit. Within the signal conditioning circuit, the two sensor signals are differentially amplified to produce a differential signal whereby the width of the slot is used to encode a binary position pulse. The spacing between the two matched MRs is such that their output resistances and, thus, their output signals become equal (crossover) in the middle of a slot whereby a wide slot causes the crossover to occur at a lower value of resistance (or output signal) than that of a narrow slot. The low level signal from a wide slot is assigned the binary value of “0” while the high level signal is assigned the binary value of “1” although the reverse assignments of binary values could also be used. Alternatively, the present invention is implementable by width encoded teeth instead of slots.